How does your product team usually work with your product marketing team with building the roadmap?

Wow, what a great question! I like to think that product marketing offers a different lens to the market landscape, competitive positioning, and product launches. As a result, I typically rely on four main activities: 

1. Include product marketing in the annual product theme and road-mapping processes 

2. Have a set sync with the product marketing to review shared performance indicators such as the top of funnel leads, website performance, and release post/notes engagement 

3. Assign tasks and responsibilities to Product Marketers in the Release Post/Notes process where they can contribute to the positioning of value before the content is released to the public

4. Have a defined set of launch processes for different categories of release features. These can be organized by impact, by pricing changes, or by a predefined cadence around a major industry event. Either way, coordinate with product marketing around the content, marketing campaigns, and sales enablement that will be required to support the product post launch. 

I think it depends on what you mean by "building the roadmap."

If you meant "how does product marketing help communicate the roadmap to sales and customers?" - this is a huge benefit to close partnership between product management and product marketing. Product marketing should be involved early and often in the launch of a new product or feature, specifically by learning the problem the roadmap item is intending to solve, understanding the market context and competitor alternatives to your product/feature, and articulating the customer benefit from implementing the product/feature. Product marketing should help product managers more clearly visually and verbally communicate the roadmap in customer facing presentations, blogs, and sales enablement.

If you meant "how does product marketing help decide what gets built?" - I think of product marketing as one of the many inputs to consult when prioritizing new features. Often, product marketing is speaking with customers about their use cases to gather their stories for external marketing and sales enablement, so they are learning about customer pain points that product management may not know - or hardships that the sales team is facing when selling or implementing the product for a customer. Other great sources of input are sales reps, sales engineers, customer support/success managers, professional services consultants, etc. Outside of your organization, getting feedback from industry analysts (if you're in enterprise software especially) can also be an interesting source of feedback, based on their following of market trends and volume of conversations they have with end users.

At Splunk, we’ve built a tightly executed roadmap update process where we spend about 2 weeks each quarter to refresh our roadmap so our customers, sales and GTM teams have the latest and greatest roadmap info. In that 2-week process, our product managers and product marketing folks actively collaborate on the roadmap updates. What does that collaboration look like? It’s product managers sharing the features and refining the messaging, customer outcomes and use cases with product marketing so we can have a solid roadmap and tell a compelling story to our customers. The marketing team also provides feedback and insights to the product team based on what they are seeing in the market and hearing from customers.

I consider product marketing managers (PMM) part of the core partner group working with Product in roadmap creation (also including engineers, design, analytics, research, and other key functions based on the role). We aim to loop in product marketing as soon as roadmapping begins, and make sure they're aligned with product on objectives for the given quarter/half - this usually involves PMM sharing insights to help pressure-test the objectives, ensure we have a good understanding of customer sentiment, etc. PMM also takes part in the feature prioritization process, both to help validate the potential impact of those features and for awareness as they build marketing plans.

We also typically include PMMs in kickoffs for individual initiatives and especially the product design process - often, the thing that is marketed becomes clear during this process (eg. what it looks like, how it specifically will solve the given user's problem, how we want to communicate this), and gives PMM a good sense of what their work will look like. In my current role, we're often having discussions at this stage about "whether the thing needs to be marketed at all" - we may be working on a behind-the-scenes change, or a very minimal feature requiring experimentation before we're confident in our approach, and that may have significant implications on the product marketing plan as a result.

Let's align on terminology first.
https://medium.com/productfolio/release-plan-vs-launch-plan-774526d2817b

The PMs lead on the Product Roadmap, but the PMMs lead on the GTM / Launch Plan. We package up our features that we want to launch into 3 -4 sizes (small , medium , large launch). Each launch classification will have it's playbook. The PMMs / PMs meet weekly to classify anything ongoing or new into these launch classifications.

If necessary the relevant PM and PMM will align on the details for how they GTM for a particular feature OR feature bundle so that we can more easily highlight the benefits to the intended target customer.

Our Product Marketing team is a key cross-functional partner and therefore provides us with suggestions, feedback, and market factors they are noticing through several channels. This is one of the ways in which our PMM team influences the roadmap.

Additionally, our product marketing and product management teams work closely together to define key elements of the product strategy (key buyers, use cases, value proposition) as well as the go-to-market strategy and enablement activities. These pre & post roadmap activities help us make sure we have alignment between what we are building and how we are talking about it in the market. Once the PM team generates the level 1 and 2 roadmaps, our PMM partners help us create alternate versions that are tailored for different audiences. For example, we create a version for internal partners like Sales that aligns with our enablement storyline, a version for current and future customers which showcases our strategic investment themes, as well as a version for industry analysts to help them understand our competitive strengths.